Management of Obesity and Obesity-Related Disorders: From Stem Cells and Epigenetics to Its Treatment.

Obesity is a complex worldwide disease, characterized by an abnormal or excessive fat accumulation. The onset of this pathology is generally linked to a complex network of interactions among genetic and environmental factors, aging, lifestyle, and diets. During adipogenesis, several regulatory mechanisms and transcription factors are involved. As fat cells grow, adipose tissue becomes increasingly large and dysfunctional, losing its endocrine function, secreting pro-inflammatory cytokines, and recruiting infiltrating macrophages. This long-term low-grade systemic inflammation results in insulin resistance in peripheral tissues. In this review we describe the main mechanisms involved in adipogenesis, from a physiological condition to obesity. Current therapeutic strategies for the management of obesity and the related metabolic syndrome are also reported.

Metformin and Vitamin D Modulate Inflammation and Autophagy during Adipose-Derived Stem Cell Differentiation.

Adipose-derived stem cells (ADSCs) came out from the regenerative medicine landscape for their ability to differentiate into several phenotypes, contributing to tissue regeneration both in vitro and in vivo. Dysregulation in stem cell recruitment and differentiation during adipogenesis is linked to a chronic low-grade inflammation and macrophage infiltration inside the adipose tissue, insulin resistance, cardiovascular disease and obesity. In the present paper we aimed to evaluate the role of metformin and vitamin D, alone or in combination, in modulating inflammation and autophagy in ADSCs during adipogenic commitment. ADSCs were cultured for 21 days in the presence of a specific adipogenic differentiation medium, together with metformin, or vitamin D, or both. We then analyzed the expression of FoxO1 and Heat Shock Proteins (HSP) and the secretion of proinflammatory cytokines IL-6 and TNF-α by ELISA. Autophagy was also assessed by specific Western blot analysis of ATG12, LC3B I, and LC3B II expression. Our results showed the ability of the conditioned media to modulate adipogenic differentiation, finely tuning the inflammatory response and autophagy. We observed a modulation in HSP mRNA levels, and a significant downregulation in cytokine secretion. Taken together, our findings suggest the possible application of these molecules in clinical practice to counteract uncontrolled lipogenesis and prevent obesity and obesity-related metabolic disorders.

Tuning Adipogenic Differentiation in ADSCs by Metformin and Vitamin D: Involvement of miRNAs.

Fat tissue represents an important source of adipose-derived stem cells (ADSCs), which can differentiate towards several phenotypes under certain stimuli. Definite molecules as vitamin D are able to influence stem cell fate, acting on the expression of specific genes. In addition, miRNAs are important modulating factors in obesity and numerous diseases. We previously identified specific conditioned media able to commit stem cells towards defined cellular phenotypes. In the present paper, we aimed at evaluating the role of metformin on ADSCs differentiation. In particular, ADSCs were cultured in a specific adipogenic conditioned medium (MD), in the presence of metformin, alone or in combination with vitamin D. Our results showed that the combination of the two compounds is able to counteract the appearance of an adipogenic phenotype, indicating a feedforward regulation on vitamin D metabolism by metformin, acting on CYP27B1 and CYP3A4. We then evaluated the role of specific epigenetic modulating genes and miRNAs in controlling stem cell adipogenesis. The combination of the two molecules was able to influence stem cell fate, by modulating the adipogenic phenotype, suggesting their possible application in clinical practice in counteracting uncontrolled lipogenesis and obesity-related diseases.

Melatonin and Vitamin D Orchestrate Adipose Derived Stem Cell Fate by Modulating Epigenetic Regulatory Genes.

Melatonin, that regulates many physiological processes including circadian rhythms, is a molecule able to promote osteoblasts maturation in vitro and to prevent bone loss in vivo, while regulating also adipocytes metabolism. In this regard, we have previously shown that melatonin in combination with vitamin D, is able to counteract the appearance of an adipogenic phenotype in adipose derived stem cells (ADSCs), cultured in an adipogenic favoring condition. In the present study, we aimed at evaluating the specific phenotype elicited by melatonin and vitamin D based medium, considering also the involvement of epigenetic regulating genes. ADSCs were cultured in a specific adipogenic conditioned media, in the presence of melatonin alone or with vitamin D. The expression of specific osteogenic related genes was evaluated at different time points, together with the histone deacetylases epigenetic regulators, HDAC1 and Sirtuins (SIRT) 1 and 2. Our results show that melatonin and vitamin D are able to modulate ADSCs commitment towards osteogenic phenotype through the upregulation of HDAC1, SIRT 1 and 2, unfolding an epigenetic regulation in stem cell differentiation and opening novel strategies for future therapeutic balancing of stem cell fate toward adipogenic or osteogenic phenotype.

Melatonin and Vitamin D Interfere with the Adipogenic Fate of Adipose-Derived Stem Cells.

Adipose-derived stem cells (ADSCs) represent one of the cellular populations resident in adipose tissue. They can be recruited under certain stimuli and committed to become preadipocytes, and then mature adipocytes. Controlling stem cell differentiation towards the adipogenic phenotype could have a great impact on future drug development aimed at counteracting fat depots. Stem cell commitment can be influenced by different molecules, such as melatonin, which we have previously shown to be an osteogenic inducer. Here, we aimed at evaluating the effects elicited by melatonin, even in the presence of vitamin D, on ADSC adipogenesis assessed in a specific medium. The transcription of specific adipogenesis orchestrating genes, such as aP2, peroxisome proliferator-activated receptor γ (PPAR-γ), and that of adipocyte-specific genes, including lipoprotein lipase (LPL) and acyl-CoA thioesterase 2 (ACOT2), was significantly inhibited in cells that had been treated in the presence of melatonin and vitamin D, alone or in combination. Protein content and lipid accumulation confirmed a reduction in adipogenesis in ADSCs that had been grown in adipogenic conditions, but in the presence of melatonin and/or vitamin D. Our findings indicate the role of melatonin and vitamin D in deciding stem cell fate, and disclose novel therapeutic approaches against fat depots.

Factors predicting worse prognosis in patients affected by pT3 N0 colon cancer: long-term results of a monocentric series of 137 radically resected patients in a 5-year period.

BACKGROUND AND PURPOSE: For patients with Stage II colon cancer, the use of adjuvant chemotherapy remains controversial. The purpose of this study was to identify clinical and/or pathological findings related to a worse prognosis in this category of patients. PATIENTS AND METHODS: We retrospectively analyzed the data of consecutive patients, extracted by an institutional Tumour Registry, admitted to an affiliated University Hospital in Milan (European Institute of Oncology) for adenocarcinoma of the colon (all sites), between 2000 and 2005, and having a final pT3 N0 pathology staging after curative surgery. Adjuvant chemotherapy was decided as a result of a medical decision within a multidisciplinary Tumor Board. RESULTS: Data of 137 patients were obtained, with a median follow-up of 77 months (range 6-131). Patients who received chemotherapy were younger than patients who did not. Nine patients out of 137 (6.5 %) died as a consequence of colon cancer recurrence; four of them had received adjuvant chemotherapy. Only histological grade III and mucinous histotype were found to impact on cumulative incidence of colon-related events (p 0.03 and 0.02, respectively); no impact was found on cumulative incidence of colonic neoplasm recurrence-related deaths (p 0.74 and 0.74, respectively). Number of analyzed LNs (lymph nodes) emerged as a factor possibly affecting the cumulative incidence of colon-related events (p 0.09) as well as the cumulative incidence of colonic neoplasm recurrence-related deaths (p 0.10). The risk of events was inversely proportional to the number of dissected LNs, even over 20 up to about 25 LNs. Never-smokers exhibited a lower incidence of colon-related events, although the difference was not statistically significant (p 0.09). All other analyzed variables did not show any impact on survival rate, including age, gender, ASA score, BMI, site of colonic neoplasm, multifocality, perivascular invasion, and use of adjuvant chemotherapy. CONCLUSIONS: Histology grading G3 and mucinous histotype were predictors of worse outcome. Efforts to improve LN evaluation should result in clinically significant improvements in outcome, and also the quality of care for patients with radically resected stage II colon cancer.

Metformin and vitamin D modulate adipose-derived stem cell differentiation towards the beige phenotype.

Adipose-derived stem cells (ADSCs) represent an ideal stem cell population for regenerative medicine. ADSC adipogenic differentiation is controlled by the activation of a specific transcriptional program, including epigenetic factors and key adipogenic genes. Under certain conditioned media, ADSCs can differentiate into several phenotypes. We previously demonstrated that bioactive molecules could counteract lipid accumulation and regulate adipogenesis, acting on inflammation and vitamin D metabolism. In the present paper, we aimed at evaluating the effect of metformin and vitamin D in targeting ADSC differentiation towards an intermediate phenotype, as beige adipocytes. We exposed ADSCs to different conditioned media and then we evaluated the levels of expression of main markers of adipogenesis, aP2, LPL and ACOT2. We also analysed the gene and protein expression of thermogenic UCP1 protein, and the expression of PARP1 and the beige specific marker TMEM26. Our results showed a novel effect of metformin and vitamin D not only in inhibiting adipogenesis, but also in inducing a specific 'brown-like' phenotype. These findings pave the way for their possible application in the control of de novo lipogenesis useful for the prevention of obesity and its related metabolic disorders.

Inflammatory Indexes as Predictive Biomarkers of Postoperative Complications in Oncological Thoracic Surgery.

The role of inflammatory responses in predicting outcomes in oncological thoracic surgery is still unclear. The aim of this study was to evaluate a series of blood count inflammation indexes as predicting factors for postoperative complications. We retrospectively studied 249 patients undergoing elective thoracic surgery in our institution between 2008 and 2020. A total of 184 patients underwent open surgery, and 65 underwent VATS. The neutrophil-to-lymphocyte (NLR), monocyte-to-lymphocyte (MLR), and platelet-to-lymphocyte (PLR) ratios, Systemic Inflammation Response Index (SIRI) were calculated preoperatively and on the first and fourth postoperative days, as well as a new derivative index, the Aggregate Inflammation Systemic Index (AISI). Univariate correlations evidenced a statistically significant association between the NLR at the fourth postoperative day and the occurrence of surgical complications in the global cohort (rho = 0.15, p = 0.03). A similar significant association with MLR on the fourth postoperative day is found in the open group (rho = -0.15, p = 0.048). NLR and LMR on the fourth postoperative day are associated with postoperative complications in the whole and open groups, respectively. Simple, easy-to-perform and inexpensive, blood cell count indexes may be useful in predicting complications in oncological thoracic surgery. A greater number of broader, prospective, randomized studies are necessary to confirm these findings.

Perianal mucinous adenocarcinoma with dysplastic polyps of the colon: A case report.

INTRODUCTION: Perianal mucinous adenocarcinoma is rarely encountered in the setting of anal neoplasms. The rarity of the disease and the paucity of publications on this topic are responsible for a lack of diagnostic and therapeutic guidelines. PRESENTATION OF CASE: An 80-year-old man with mucinous adenocarcinoma of the anal canal associated with dysplastic polyps of the colon was treated by multiple endoscopic polypectomies and abdomino-perineal resection of the rectum. We discuss the management of this rare case from the diagnosis up to one-year follow-up. DISCUSSION: Perianal mucinous adenocarcinoma is a very rare entity frequently combined with chronic fistulas. Inflammatory symptoms may mislead its diagnosis, which is often delayed. The unique association between perianal mucinous adenocarcinoma and dysplastic polyps of the colon, that we have reported, may suggest a secondary etiology. High clinical suspicion is important for early and correct diagnosis, which should be based on endoanal ultrasound and/or magnetic resonance imaging followed by deep tissue biopsies. CONCLUSION: We stress the importance of accumulating such cases in the literature. The understanding of the etiopathogenic mechanisms may lead to the development of novel diagnostic and therapeutic protocols.

Adipose-Derived Stem Cell Features and MCF-7.

Human adipose tissue-derived stem cells (hADSCs) are highly suitable for regeneration therapies being easily collected and propagated in vitro. The effects of different external factors and culturing conditions are able to affect hADSC proliferation, senescence, differentiation, and migration, even at the molecular level. In the present paper, we exposed hADSCs to an exhausted medium from the breast cancer cell line (MCF-7) to evaluate whether the soluble factors released by these cells may be able to induce changes in stem cell behavior. In particular, we investigated the expression of stemness-related genes (OCT4; Sox 2; Nanog), the cell-cycle regulators p21 (WAF1/CIP1) p53, epigenetic markers (DNMT1 and Sirt1), and autophagy-related proteins. From our results, we can infer that the exhausted medium from MCF-7 is able to influence the hADSCs behavior increasing the expression of stemness-related genes, cell proliferation, and autophagy. Polyamines detectable in MCF-7 exhausted medium could be related to the higher proliferation capability observed in hADSCs, suggesting direct crosstalk between these molecules and the observed changes in stem cell potency.

Extracts from Myrtle Liqueur Processing Waste Modulate Stem Cells Pluripotency under Stressing Conditions.

Nutraceuticals present in food are molecules able to exert biological activity for the prevention and treatment of various diseases, in form of pharmaceutical preparations, such as capsules, cream, or pills. Myrtus communis L. is a spontaneous Mediterranean evergreen shrub, widely known for the liqueur obtained from its berries rich in phytochemicals such as tannins and flavonoids. In the present study, we aimed to evaluate the properties of myrtle byproducts, residual of the industrial liqueur processing, in Adipose-derived stem cells (ADSCs) induced at oxidative stress by in vitro H2O2 treatment. Cells were exposed for 12-24 and 48h at treatment with extracts and then senescence-induced. ROS production was then determined. The real-time PCR was performed to evaluate the expression of inflammatory cytokines and sirtuin-dependent epigenetic changes, as well the modifications in terms of stem cell pluripotency. The ß-galactosidase assay was conducted to analyze stem cell senescence after treatment. Our results show that industrial myrtle byproducts retain a high antioxidant and antisenescence activity, protecting cells from oxidative stress damages. The results obtained suggest that residues from myrtle liqueur production could be used as resource in formulation of food supplements or pharmaceutical preparations with antioxidant, antiaging, and anti-inflammatory activity.

Deciduoid mesothelioma of the thorax: A comprehensive review of the scientific literature.

OBJECTIVE: Deciduoid mesothelioma is a rare variant of malignant epithelioid mesothelioma. It often involves the peritoneum, but also thoracic cases have been reported. The aim of the present review is to describe the demographic, clinical, radiological, and pathological features of such a rare variant of thoracic mesothelioma, and the state of the art regarding the therapeutic approaches currently available. DATA SOURCE: English-language articles published from 1985 to June 2016, and related to thoracic deciduoid mesothelioma cases were retrieved using the Pubmed database. STUDY SELECTION: The search terms were "mesothelioma," "thoracic mesothelioma," "epithelial mesothelioma," "pleural mesothelioma," and "deciduoid mesothelioma." RESULTS: Forty-four cases included in 16 articles, published in the period under investigation, were analyzed in detail. CONCLUSIONS: The mean age of the patients was 63 years, and the male to female ratio 1.7:1. Approximately 58% had exposure to asbestos, and 73% had a smoking history; familiarity was rarely reported. The most common anatomical site of origin was the right pleura, and the most frequent clinical manifestations were chest pain, dyspnea, cough, and weight loss. Thoracic X-ray and computed tomography were the imaging techniques most employed for diagnosis and surgical planning. The pathological diagnosis was obtained by examination of surgical or biopsy specimens in most cases. The best treatment strategy of deciduoid mesothelioma is a matter of debate; nevertheless a multidisciplinary approach is currently the best option for the choice of the adequate therapeutic scheme.

Red cell distribution width and mean platelet volume as predictors of anastomotic dehiscence in colorectal surgery A pilot multicenter case-match study.

AIM: One of the most serious complications in modern colorectal surgery is the occurrence of an anastomotic dehiscence. The aim of this study was to evaluate the role of preoperative red cell distribution width (RDW) and mean platelet volume (MPV) as predictors of anastomotic dehiscence in elective surgery for colorectal cancer. MATERIALS AND METHODS: Forty-two patients with a clinically manifested anastomotic dehiscence after oncological colorectal surgery, and 42 controls matched for age, sex, pathological stage and tumor localization were enrolled. Correlations between the preoperative RDW and MPV values and anastomotic dehiscence were investigated. RESULTS: Both the median RDW value (14.4 % vs 13.1%; p=0.007) and the median MPV value (8.0 fL vs 7.5 fL; p=0.037) were significantly higher in patients with anastomotic dehiscence than in those without. In multiple regression analysis only the RDW remained significantly associated with anastomotic dehiscence. CONCLUSIONS: The preoperative values of RDW may be useful in predicting anastomotic damage in elective oncological surgery. KEY WORDS: Anastomotic Dehiscence, MPV, RDW.

A rationale multidisciplinary approach for treatment of esophageal and gastroesophageal junction cancer: Accurate review of management and perspectives.

Cancer of the esophagus and of gastroesophageal junction can be cured, even if with lacking cure rate. Different approaches have been developed, mostly when carcinoma has loco-regional pattern. Multimodality therapy showed a survival rate superior than 10% if compared to a single approach. This is a systematic review, carried to assess the following matters: Which therapeutic opportunities are available? Who could benefit of them? Which adverse reactions could possibly verify? How can physicians definitely choose the proper strategy? Which is the role of surgery? We mean to give either General Practitioner or specialists clear and efficient updates about current treatment of this tumour, starting from physical examination. Four eminent guidelines were consulted for our study: Cancer Care Ontario's Program in Evidence-Based Care, NCCN, Belgian Health Care Knowledge Centre and Esmo.

Aggressive Surgical Approach for Treatment of Primary and Recurrent Retroperitoneal Soft Tissue Sarcoma.

To analyze treatment and survival in a series of resected patients with primary or recurrent retroperitoneal sarcoma (RPS) treated and prospectively followed at a single institution. Between July 1994 and December 2015, 89 patients (36 M, 53 F; mean age 60 years, range 25-79) were evaluated. For the purpose of analysis, complete resection was defined as removal of gross tumor with histologically confirmed clear resection margins. Eighty-three out of the 89 patients (93%), 46 of whom affected by primary RPS, and 37 by recurrent RPS, underwent surgical exploration. Sixty-two had a grossly and microscopically complete resection. Fifty-three out of 83 patients (64%) underwent removal of contiguous intra-abdominal organs. Preoperative mortality was nil and significant preoperative complications occurred in six cases only (7%). High-grade tumor pointed out to be a significant variable for a worse survival in all 83 patients amenable to undergo surgical resection (57% 5 years survival for low grade vs 14% for high grade; P = 0.0004). Among completely resected patients, only histologic grade clearly affected disease-free survival (72% 5 years survival for low grade vs 50% for high grade; P = 0.04), while the role of preoperative blood transfusions (67% 5 years survival for non-transfused patients vs 29% for transfused patients; P = 0.05) has to be evaluated in connection to patient complexity. Histological grade and recurrence are the most valuable prognostic predictors; in this clinical subset, an aggressive surgical approach in both primary and recurrent RPS is associated with a best long-term survival and disease-free survival.

Emergency surgical conditions after biliopancreatic diversion.

BACKGROUND: Urgent late complications of biliopancreatic diversion (BPD) are rare and often require the experience of a bariatric surgery team for their immediate resolution. METHODS: The present work analyzes the incidence of emergency surgical conditions in a group of 138 patients who had undergone classical BPD, with a mean follow-up of 60 months (24-96) after BPD. RESULTS: Urgent surgical intervention was necessary in 9 patients out of 138 (6.5%): 7 (5%) were for intestinal obstruction (4 of the biliopancreatic limb and 3 of the alimentary tract); 2 (1.4%) were for stomal ulcer with complications (1 massive hemorrhage and 1 perforation). CONCLUSIONS: These complications of BPD are common to all GI operations, and thus are not specific to the type of surgery. We emphasize the importance of early diagnosis and treatment, particularly in regard to intestinal obstruction, because delay could have dramatic consequences.

Prophylaxis of venous thromboembolism in bariatric surgery.

Patients with morbid obesity who undergo bariatric surgery are usually considered at high risk of developing venous thromboembolism. Considering that deep vein thrombosis is often asymptomatic, primary prevention is the key to reducing morbidity and mortality. Between 1995 and 2003, 151 patients underwent surgery for morbid obesity at the Obesity Surgery Centre-University of Sassari. At the beginning of our experience in this field, in the first 65 cases, prophylaxis of thromboembolism consisted in a single intravenous injection of heparin sodium at the time of induction of anaesthesia. The dose of heparin ranged from 2500 to 5000 IU according to weight and any diseases associated with obesity. In a later stage of our experience (86 cases) we modified the drug therapy and used low doses of calcic heparin: the dose was obtained by daily monitoring of Pt, TT and aPTT in order to obtain good anticoagulation. This treatment was usually begun 4-5 days before the operation and continued until the patient was discharged (8-9 days). In the first group of patients we had 2 cases (3%) of fatal acute pulmonary embolism. In the second group 1 (1.16%) case of non-fatal pulmonary embolism developed on postoperative day 20. No clear consensus emerges from the literature as to the best approach to reduce the risk of thromboembolism in bariatric surgery to a minimum. Our experience suggests that "personalized heparin prophylaxis" before, during and after bariatric surgery could be the key to reducing morbidity and mortality.

Cost and morbidity analysis of chest port insertion in adults: Outpatient clinic versus operating room placement.

BACKGROUND: Totally implantable venous access devices (TIVADs) represent a convenient way for the administration of medications or nutrients. Traditionally, chest ports have been positioned by surgeons in the operating room, however there has been a transition over the years to port insertion by interventional radiologists in the radiology suite. The optimal method for chest port placement is still under debate. MATERIALS AND METHODS: Data on all adult patients undergoing isolated chest port placement at our institution in a 12-year period were retrospectively reviewed. The aim of this cohort study was to compare cost and morbidity for chest port insertion in two different settings: outpatient clinic and operating room. RESULTS: Between 2003 and 2015 a total of 527 chest ports were placed in adult patients. Of them, 262 procedures were performed in the operating room and 265 procedures were undertaken in the outpatient clinic. Patient characteristics were similar and there was no significant difference in early (<30 days, p = 0.54) and late complications (30-120 days, p = 0.53). The average charge for placement of a chest port was 1270 Euros in the operating room versus 620 Euros in the outpatient clinic. CONCLUSION: Our results suggest that chest ports can be safely placed in most patients under local anesthesia in the office setting without fluoroscopy or ultrasound guidance. Future randomized controlled studies may evaluate if surgeons or interventional radiologists should routinely perform these procedures in a dedicated office setting and reserve more sophisticated facilities only for patients at high risk of technical failure.

Surgical outcomes in patients with hepatic synchronous and metachronous colorectal metastases.

AIM: To evaluate the impact of several clinical and pathological factors on the outcomes of surgery for hepatic colorectal cancer metastasis. METHODS: Eighty-four liver metastasectomies in 77 consecutive patients with 90 colorectal cancer hepatic metastases were performed in our institution from 2009 to 2014. Surgery was carried out in 75 cases, as two patients were not eligible for surgery. Among them 43 (Group A) were affected by synchronous, and 32 (Group B) by metachronous lesions. Furthermore, 9 reoperations were performed in patients with initially synchronous lesions. The follow-up after surgery included total body CT scan every 3 months for the first year, and every 6 months for 4 years thereafter. Blood level of CEA was determined every 3 months. RESULTS: The univariate analysis evidenced significantly more recurrences in patients with synchronous lesions (p=0.011), and higher grade, pN stage and CEA blood levels. In multivariate logistic regression analysis the statistically significant parameters found were: the pT stage (OR: 3.92, p = 0.039), the use of adjuvant chemotherapy for the colonic tumor (OR: 0.19, p = 0.025), and the adjuvant chemotherapy (OR: 4.11, p = 0.048). The global survival was 32 patients (41.5%), 17 with synchronous and 15 with metachronous lesions, and a significant difference in long-term survival between these two groups was found (p = 0.008). CONCLUSIONS: The most relevant prognostic factor in patients with hepatic colorectal cancer dissemination is the timing of metastasis; the metachronous lesions present better survival when surgically treated. KEY WORDS: Colorectal cancer, Liver, Metastasis, Surgery.

Perineural infiltration as a prognostic factor in surgically treated gallbladder cancer A single center experience and literature review.

INTRODUCTION: Gallbladder cancer (GBC) is the most incident cancer of the biliary tract with only 5-13% of the sufferers surviving for five years. The aim of this study was to evaluate the prognostic role of perineural invasion (PNI) and its association with several clinicopathological variables in a cohort of surgically treated patients, and through a comprehensive review of the scientific literature. MATERIALS AND METHODS: Twenty-five consecutive patients submitted to curative surgery for GBC from 2008 through 2016 were enrolled. Demographic, clinical and pathological data were retrieved from medical files, and specimens were re-examined by two experienced pathologists. The Pubmed database was searched for articles reporting on perineural infiltration on gallbladder cancer. RESULTS: Perineural invasion was observed in 14 (56%) cases, and it was more frequent in higher pathological stages. A statistically significant association was found with high preoperative serum Ca 19-9 levels. Fourteen (56%) patients died during the follow-up; survival was lower in patients with perineural invasion in comparison to those without, but not statistically significant. Twelve English-language articles reporting on PNI were retrieved and discussed. CONCLUSIONS: Perineural invasion is associated with higher stage and poorer survival in surgically treated GBC patients. In patients with locally advanced GBC resection of the extrahepatic biliary duct and frozen section examination of the distal stump must be taken into consideration, especially in cases of tumor arising from the hepatic side of the gallbladder. In cases without residual disease but with pathological evidence of PNI, a careful follow-up is suggested to early detect recurrences. KEY WORDS: Adenocarcinoma, Cancer, Gallbladder, Perineural infiltration, Surgery.